Analog Devices Inc./Maxim Integrated MAX6351SYUT

Overview

The MAX6351SYUT from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with two active-low push-pull reset outputs (RST1 referenced to VCC1, RST2 referenced to VCC2), factory-set thresholds of 2.93V (VTH1) and 2.19V (VTH2), 20µA supply current, and guaranteed RESET validity down to VCC1 ≥ 1.0V or VCC2 ≥ 1.0V - used in multivoltage embedded systems requiring reliable power-on and brownout detection.

For engineers reviewing the MAX6351SYUT datasheet, MAX6351SYUT pinout, MAX6351SYUT application, or MAX6351SYUT equivalent, this device supports precise dual-rail monitoring in portable equipment, intelligent instruments, and industrial controllers where independent reset assertion per supply rail is required and low quiescent current is critical.

Technical Context

The MAX6351SYUT implements dual independent voltage comparators with hysteresis, each feeding a dedicated reset generator with 100ms minimum power-on-reset pulse width. Its push-pull outputs drive directly into CMOS inputs without external pull-ups, and internal glitch filtering ensures immunity to sub-100ns MR input transients.

Reset assertion occurs if either VCC1 drops below 2.93V (±45mV over temperature) or VCC2 drops below 2.19V (±45mV over temperature); both outputs remain valid as long as at least one supply stays ≥1.0V, enabling robust operation during asymmetric supply sequencing or partial brownout conditions.

Key Specifications

Pinout & Package

MAX6351SYUT is housed in a 6-pin SOT23 package (U6-1 outline, land pattern 90-0175), with exposed pad not electrically connected. Pin 1 is RST1 (active-low push-pull, referenced to VCC1), Pin 2 is GND, Pin 3 is MR (debounced manual-reset input), Pin 4 is VCC2, Pin 5 is RST2 (active-low push-pull, referenced to VCC2), and Pin 6 is VCC1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-voltage supervisory applications.

Compared with MAX6351SYUT, MAX6353SYUK-T reduces pin count and cost but sacrifices independent VCC2 supervision, while TPS3808G33DBVR offers lower quiescent current but cannot replace dual-threshold functionality - MAX6351SYUT remains optimal for true dual-rail integrity assurance.

Availability

MAX6351SYUT is available at Aetrix Electronics and suitable for portable/battery-powered equipment, intelligent instruments, and multivoltage systems requiring stable component supply, guaranteed industrial temperature operation, and precise dual-threshold supervision.

Supply support for MAX6351SYUT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for industrial, computing, and communications applications.

The MAX6351–MAX6360 family delivers integrated dual- and triple-voltage supervision for multirail embedded systems, eliminating discrete solutions while guaranteeing reset validity across wide supply and temperature ranges.

FAQ

What are the exact voltage thresholds programmed into the MAX6351SYUT?

The MAX6351SYUT has factory-set thresholds of 2.93V for VCC1 (±45mV over –40°C to +85°C) and 2.19V for VCC2 (±45mV over –40°C to +85°C), as defined by the "SY" suffix in the Voltage Threshold Levels table. These values are laser-trimmed during production and do not require external components for calibration. The MAX6351SYUT datasheet specifies these thresholds in the Electrical Characteristics table under VTH1 and VTH2 columns.

Does the MAX6351SYUT support operation when one supply drops below 1.2V?

Yes - the MAX6351SYUT guarantees valid RST1 and RST2 outputs as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V, per Absolute Maximum Ratings and Electrical Characteristics. This allows continued reset assertion during deep brownout events where one rail collapses while the other remains marginally active. The MAX6351SYUT maintains this behavior across its full –40°C to +85°C operating range.

Can the manual-reset input (MR) of the MAX6351SYUT be driven directly from a microcontroller GPIO?

Yes - the MR input of the MAX6351SYUT is TTL/CMOS-compatible with internal debouncing and a ~63.5kΩ pull-up resistor. It accepts logic-low pulses as short as 1µs and operates with VIH ≥ 2.3V (for standard versions) or VIH ≥ 0.7×VCC1 (for _Y variants). A microcontroller GPIO can drive MR directly without external components, provided the GPIO output voltage meets the MR input threshold specification. This behavior is confirmed in the MAX6351SYUT Electrical Characteristics table.

What is the reset timeout period for the MAX6351SYUT after power-up?

The MAX6351SYUT provides a minimum reset timeout period of 100ms after VCC1 and VCC2 exceed their respective thresholds, with typical values of 180ms and a maximum of 280ms. This power-on-reset pulse width ensures sufficient time for microprocessor and peripheral initialization before release. The timing is internally generated and does not depend on external capacitors - a key feature documented in the MAX6351SYUT Electrical Characteristics table under tRP.

Is the MAX6351SYUT pin-compatible with other devices in the MAX6351–MAX6360 family?

The MAX6351SYUT uses a 6-pin SOT23 package (U6-1) and shares identical pinout with all other 6-pin variants in the family (e.g., MAX6355, MAX6356, MAX6358–MAX6360), including RST1/RST2/GND/MR/VCC2/VCC1 assignments. However, functional differences exist: MAX6351SYUT provides two push-pull outputs, while MAX6355 offers RSTIN instead of RST2, and MAX6358 adds WDI. So while mechanical pinout is identical, electrical function per pin varies - MAX6351SYUT is not a drop-in replacement for non-MAX6351 variants.